Color analyzing and synthesizing device



June 16, 1953 H.- W. HELDING 2,641,853

COLOR ANALYZING AND SYNTHESIZJING msv'rcm Filed July 16, 1949 5 Sh'ets-Sh''et 2 wwzz dune 16, 1953 H. W. HELDING COLOR ANALYZING AND SYNTHESIZING DEVICE 5 Sheets- @Shee't 3 Filed July 16, 1949 June 16, 1953 H. w. HELDING 2,641,853

COLOR ANALYZING AND sYNmEsIzm; DEVICE Filed July 16. 1949 5 Sheets-Sheet 4 June 16, 1953 H. w. H ELDlN 2,641,853

COLOR ANALYZING AND smmssxzmc DEVICE Filed July 16, 1949 s Sheet s$heet 5 awe/hazar- Patented June 16, 1953 UNITED sr r s PATENT OFFICE COLOR ANALYZING AND SYNTHESIZING DEVICE Herbert W. Helding, Highland Park, Ill.

Application July 16, 1949, Serial No. 105,191

4 Claims. 1

This invention relates generally to a mechanical device capable of determining the percentage of certain colors which comprise a given composite color, or conversely, capable of producing the appearance of a composite color by means of predetermined percentages of said colors.

While not limited thereto, my invention is especially useful in the photoengraving art where it is desired to reproduce color photographs by means of half-tone plates, each representing a different one of a group of known process colors being used for printing the reproduction. Many other uses will be pointed out hereinafter, but emphasis will be placed upon the aforementioned use because of the extremely great saving in time, effort, and expense by the use of my device.

A typical method of making color reproduction half-tones by the presently used techniques requires great skill and judgment besides being tedious and time consuming. First a color positive is made from the original negative. This is the reference copy and must constantly be con-' sulted for comparison throughout the entire process. Next, four color separation negatives are made. This is done by taking photographs of the copy using various filters which eliminate or enhance the various colors. The basic process colors used in photoengraving are usually black, blue, red and yellow, and this invention will be discussed as though such colors are being used, but it is desired to point out that the invention is capable of being used with a different number of colors. I

Continuing with the description of the usual process, if the exposures for producing the four color separation negatives are perfectly correct, the correct percentage of the respective basic colors will appear as the percentage densities of the emulsions of the respective negatives. lowing this, positives are made of the negatives so that the craftsman can more carefully judge whether the percentagewise separation of the color is accurate. The positives are dot etched reproduction of the copy color print, but this Folor altered at this pointin order to assist in the rarely, if ever, occurs.

There follows a long drawn out period of constant taking or drawing (as it is known in the trade) of four color registration proofs and alteration of the plates to attempt to cause the final print to conform to the copy. The plates have to be rubbed, burnished, re-etched, built up, and many, many proofs drawn. Often, the plates have to be entirely re-made. This process ties up the copy; keeps the shop equipment unneccessarily in use; occupies the full time of highly skilled and highly paid workmen; and not :al- Ways results in a satisfactory final print.

One of the principal objects of this invention is to considerably reduce the time and expense involved, obtain better results, and enable lessskilled workmen to produce satisfactory halftone color plates.

Another object of the invention is to enable simple standardization of colors,'b0th basic and composite, whereby it is possible to determine the composition of a composite color, or perfectly reproduce a given composite color when the percentages of basic colors are known.

My invention provides a housing having mounted therein four cylindrical members each having two peripheral transparent bands or strips upon which are sequentially arranged sections of printed half-tone dots, graduated percentagewise. Each member has a band of black dots and a band of dots of one of the process colors. Each member thus represents a color of the four basic process colors being used to obtain a reproduction or determine the percentages of a given composite color. Obviously'the members representing black has both bands black. The sections of the black bands of each member (and only one of the black bands of the member representing the color black) are all provided with indicia giving the percentage represented by the section, both as to the black dots and colored dots of the parallel band on the other end of the member. Obviously circumferentially aligned sections of the parallel bands are intended to have dots representing identical percentages, albeit of different color.

The cylindrical members are all mounted independently to rotate upon a common axis. Each is rotatable to any one of a number of positions representing a percentage of color, and in any such position, all of the colored bands are superimposed with one section of each in alignment with a single section of each of the others and a window of the housing. This is the window which is intended to show the composite color. The housing has four additional windows, and the black section of each of the black bands of each member which corresponds to the percentage section appearing at the composite window will appear at the respective windows, alone, and with out any other black or colored section. There is provided a fluorescent lamp illuminating all of the windows from the rear of the transparent portions of the members so as to provide as nearly as possible daylight illumination. Each of the members is arranged to cooperate with a detent mechanism to cause perfect alignment of any section with a window.

Thus, for any given composite color and position of the cylinders, at the five windows there will appear the following:

At the composite window there will appeal a composite color made up of say "a percent black half-tone dots, 17 percent blue half-tone dots, percent red half-tone dots, and "(1 percent yellow half-tone dots. The appearance of the color will be precisely as it would be printed from four half-tone plates of the respective percentages of half-tone colors. At the black window there will appear a section of half-tone black dots, whose size is identical to the size of the black dots of the section appearing at the composite window, as well as a notation reading the percentage a. At the blue window there will appear a section of half-tone black dots, whose size is identical to the size of the blue dots of the section appearing at the composite window, as well as a notation reading the percentage b. At the red window there will likewise appear a section of black half-tone dots of size corresponding to percentage 0 and at the yellow window there will appear a fourth section of black halftone dots of a size corresponding to the percentage d. Obviously there will be notations at each window stating what the percentages c and "(1 are.

It will be seen that for any given setting of the device, the observer will have the composite color appearing before him exactly .as it will print; there will appear four black half-tone sections each marked with a value which is the respective percentage of the color represented by its window which appears at the composite window; the four black halt-tone sections will have respective dot size equal to the size of the colored dot appearing at the composite window. 7

Many objects and advantages will appear as a detailed description of the invention as set forth in connection with drawings of said embodiment in which:

vFig. 1 is a perspective view showing a device constructed in accordance with my invention.

Fig. 2 is a partial plan view of the face of the device showing the windows thereof in detail.

Fig. 3 is a sectional view of the device with portions broken away to show the details of construction thereof.

Fig, 4 is a sectional view taken through the device on the line 44 of Fig. 3 and in the indicated direction.

Fig. 5 is a perspective View of the linkage and mechanism for operating the masking device used screws 3 l.

4 to exhibit only a very small portion of the color appearing at the composite window.

Fig. 6 is a sectional view taken on the cylindrical member axis and showing a side view of one of the member rotating and detent wheels.

Fig. 7 is a partial sectional view through one of the members and its rotating and detent wheel.

Fig. 8 is a developed view showing the bands carried by one of the cylindrical members.

Fig. 9 is an enlarged view to show the manner that the half-tone dots representing difierent percentages, are formed in the various sections of any band.

Fig. 10 is an enlarged plan view showing the general appearance of a composite color at the composite Window, and showing the manner in which said color is made up of four half-tone sections.

Fig. 11 is an exploded perspective view which shows how the half-tone sections printed on the transparencies are superimposed to provide an eventual composite color, I I

Fig. 12 is a greatly enlarged view showing th relative positions of the various colored half-tone dots of a composite color.

Figs. 13 to 16 inclusive are diagrammatic views which show the orientations for the various colors on the colored band of each cylinder.

Fig. 17 is a schematic View showing the align ment of the sections of the parallel bands of a given cylinder with the symbolic representation used to indicate that the two bands move simultaneously.

Referring now to the drawings, the reference character 20 designates generally my new device, same comprising a housing formed with front and rear walls 2| and 22, a bottom wall 23, side walls 24 and 25, and an inclined top wall 25 with a horizontally disposed extension The housing will be referred to collectively by the character and is preferably formed of sheet metal, bent or stamped to formation and held together in any suitable manner, such as for example by the Padded feet 32 are secured to the bottom wall 23 to prevent marring of polished surfaces. Louvres are provided at 33 in the front wall 2! and at 34 in the top wall extension 2'! to provide ventilation for the interior of the housing 30.

Within the housing there is mounted a central fixed shaft 35 which extends from wall 26. to wall 25 along the length of the housing 35 and is mounted in hangers such as for example the collar 36-secured to the wall 2 3- by screws 3? as shown in Fig. 3. Mounted upon the shaft 35 for rotation relative thereto, and independent of each other, are provided four cylindrical members 46, ll, 32 and 43, representing respectively the colors yellow, red, blue, and black. Each member includes a manually movable detent wheel, as indicated respectively at 54, 45, 46 and ll'. The wheels are constructed identically, and one is illustrated in Figs. 6 and '7. Each wheel has an annular rim portion, the rim portion of the wheel 54 being designated 48 and that of the wheel being designated '39 (Fig. 4). The rim portions of wheels 66 and 47 are designated 5!! and 51 respectively; The centers of the wheels are therefore substantially free and unobstructed, except for a single arm such as shown at 52 and 53 connected to its respective rim 48 and 49, each of which arms has a central hub 54 and 55 rotatable upon the shaft 35.

The rims 48, 49, 50, and 5| are provided with circumferentially spaced detent recesses 56 which underside of the member 61.

are adapted to cooperate with spring pressed detent devices 51. All of the detent devices are identical and there is one provided for each of the Wheels 44 to 41. As shown in Fig. 4, each detent device includes a flat base portion 58 secured to the bottom wall 23 by means of the screw 59 for example, and having a pair of curved arms Bil formed out of some resilient material such as for example, spring wire, and having a roller 5| rotatably mounted on the end thereof. The roller 6| is of such diameter as to engage within the detent recesses 56 and the arms 60 are biased to urge said roller against the periphery of the respective wheel. As will be seen from Figs. 3 and 4 the rollers 60 are arranged to align with the respective wheels.

The top wall 26 of the housing 30 has a rectangular opening provided therein as shown at I55 and extending throughout substantially the length thereof, but said opening is covered by three members 66, 61, and 68 in the manner shown in Fig. 4.

In said Fig. 4 which is a sectional view taken through the device at the position of the member 61, there is shown a backing member 69 for the member 61 upon which may be printed indicia to be explained hereinafter. Thus the member 61 is preferably transparent and may be formed of glass or methyl methacrylate resin. The member 61, as are the other members 66 and 68, may be secured byv means of screws such as shown at 10, passing through the wall 26, the member 61 and engaged within a strap or plate 1| upon the Such attaching means may be provided along upper and lower edges of the members 66, 61, and 68.

The members 66, 61, and G8 are of such size and spaced from one another and the ends of the rectangular opening 65 as to leave spaced slots 12, 13, 14, and 15. The slots 12, 13, 14 and 15 are aligned with the wheels 44, 45, 46, and 41 and a segment of each rim is adapted to protrude through the respective slots as shown in Fig. 1. Thus, it is possible to grasp the portion of each wheel protruding and rotate that wheel to any of the positions determined by the detent devices 51. The outer edges of the wheels between the detent recesses 56 are provided with numbers shown at 16 for a purpose to be explained. There are five windows provided in the cover members 66, 61, and 68 as clearly shown in Fig. 2. The yellow window 11 is provided on the. left side of member 66, while the red window 18 is provided on the right side of said cover member 6'5. Thecentral cover member 61 has a single large composite window 19. In similar manner the covermember 68 is provided with a blue window 80 on the left and a black window 8| on the right. The detent devices 51 cooperate with the recesses 56 of the respective wheels so that when the roller 6| of any device is engaged'within a recess 56, that wheel has a certain numeral 16 aligned with the window alongside the same.

Obviously, the windows above described may be formed in any other manner, and without the use of the cover members 66, 61, and 68, and the specific description is not intended to limit the invention.

For the sake of appearance as well as efliciency the operational face of the device is symmetrical as noted in Fig. 2, but obviously, if one realizes that there will be four transparencies superimposed beneath the composite Window 19 as shown in Fig. 3, the constructions comprising the four cylindrical members 40, 4|, 42, and 43 will not be symmetrical.

Hereinafter follows a description of the respective cylindrical members 40, 4|, 42, and 43.

The member 4|) comprises a wheel 44 described hereinabove which is fixed to the left end of an elongated sleeve 83 by means of a set screw 84 or the like. At its right end, the sleeve 83 has a small wheel 85 secured thereto by the set screw 86 passing through the hub 81. The wheel 85, although smaller in diameter than the wheel 44 has the indentical construction, including a single arm (not shown) and an unobstructed space within the rim 88. The sleeve 83 is positioned upon the shaft 35 by means of the cotter pins 89 and 99 which pass through appropriate holes drilled in the shaft to accommodate the same. Associated anti-friction washers are indicated at 9| and 92. As shown in Figs. 6 and 7 the wheel 44 has a cylindrical transparent member I09 secured thereto about the rim thereof, concentric with the axis of the wheel 44 and spaced inwardly a sufiicient distance so that the surface of the member I00 will not engage against the bottom surface of the cover member 66. A complete development of the member I is shown in Fig. 8, but same will be explained in connection with the manner of use of the device hereinafter.

The wheel 44 has been described asa single member, but it should be obvious to those skilled in the art that same may be formed of two separate members, an outer annular member comprising that portion of the rim 48 circumferentially outside of the member I00, and an inner wheel, having a diameter equal to the inner diameter of the member I00 and being provided with the hub 54 and the arm 52 and the remainder of the rim 48. The member Hill will thus be sandwiched between the nested-portions making up the wheel 44. The drawings have shown this composite construction, but it is not desiredito be limited thereby. For sake of clarity, the composite rim will be considered as a single rim 48 in the case of the wheel 44 and as the single rims 49, 50, and 5| of the respective wheels 45, 46, and 41.

The construction of the wheel 88 will thus be identical with the construction of the portion of the wheel 44 within the confines of the member I00.

The member I00 has a plurality of circumferentially aligned sections I 0| to III inclusive which comprise printed rectangles adapted to align with the Window 19 as the wheel 44 is rotated.

There is a second transparent cylindrical member II2 which is secured to the peripheral edge of the wheel 88 and is adapted to rotate there with. The member I I2 is also provided with rectangular printed sections M3 to I23 inclusive, which are of the same size as the sections of cylinder I 00 considered in a circumferential di rection, but which are twice as long as the sections of the member I90 considered in a direction parallel with the axis of rotation of the member I I2. The sections of the member i2 are intended to align with and be seen through the win dow 19, and the diameter of the member IE2 is such as to clear the inner surface of the cover member 61 and its backing member 69.

Rotation of the wheel 44 will cause simultaneous rotation of the transparent cylinders ifiii and H2 by reason of the physical connection of the sleeve 83 between the wheels 44 and 88. Such rotation can therefore be considered as the rotatlon of a single cylindrical member designated generally 40.

The second cylindrical member is designated M. Note that there is a considerable space between the wheels 4 and 88, and the wheel 45 of member 4| and its transparent cylinders are adapted to be located thereat. The wheel 45 is provided with a hub 55 loosely mounted upon the sleeve 83 so as to be rotatable relative thereto and independently of the wheel 44. There is a collar I26 secured to the sleeve 33 by the set screw 27 on one face of the hub 25, and an antifriction washer on the other face of the hub 55 between the hub 53'' and said hub It will be seen that the wheel is rotatable upon the shaft 35, but incapable of axial movement.

On the left surface of the wheel 45 and secured circumferentially about the rim 49 there is provided a transparent cylinder E29 whose construction is identical to the construction of the member I00. Obviously the sections, one of which is shown in Fig. 2 at see are adapted to align with the window '5. Again, as in the case of the wheel M, the wheel 45 may be made up of com posite sections, such as for example, an outer annular member having the detent recesses 55, and aninner wheel of smaller diameter carrying the arm 53 and the hub 55. These may be nested as shown in Fig. 3 with an annular spacer I3I between the transparent cylinders 529 and I32 carried by the wheel 55. The transparent cylinder I32 is secured to the rim 59 on the right hand side of the wheel 45 and has the identical construction as the transparent cylinder H2,

albeit same is larger in diameter than the cylinder NZ to enable the cylinders to telescope one within the other and rotate independently without touching one another. Obviously the sections of the cylinder I 32 (not shown) are intended to align with the window #9 in registry with sections of the cylinder I I2.

If desired, the wheels 4% and 25 instead of being made up of nesting portions could be formed as integral members having circumferential grooves in the surfaces thereof within which may be secured the transparent cylinders hereinbefore discussed. It is desired to point out at this point that all of the cylinders of my invention are preferably formed as strips of transparent cellulose bent into such cylinders, but printed with the various sections in a manner to be described prior to formation.

Rotation of the wheel 45 will cause simultaneous rotation of both transparent cylinders I29 and I 32 by reason of the attachment thereof to the respective surfaces of said wheel 45, and such rotation will therefore be considered the rotation of a single cylindrical member designated M.

The next cylindrical member mounted upon the shaft 35 is the member which is constructed somewhat like the member ii. There is provided a wheel having a hub I35 which isloose- 1y mounted upon a sleeve I35 (comprising a portion of the member 133) and fixed against axial movement along said. sleeve by reason of the hub It? of the wheel 538' and washer I39 on one side, and the collar I49 on the other. The collar I4!) is secured to the sleeve E35 by a set screw I4i. Upon the left surface of the wheel 45 and circumferentially mounted about the rim 59 is a transparent cylinder M2 larger in diameter than the similarly positioned cylinder I 32 of the wheel 45. The cylinder N32 is otherwise identical in construction to cylinder I32 and has similar printed sections (not shown) also adapted to align with the window I9. Obviously the diameter of cylinder I42 is such as to clear the inner surface of the cover member 67, and its backing member 69. On its right hand surface, the wheel 46 has a second cylinder I44 secured to the rim and having a construction identical with the cylinder I09. There are rectangular sectionswhich are adapted to align with the window 80, one of which is shown at I45 in Fig. 2.

Rotation of the wheel 45 will cause simultaneous rotation of both transparent cylinders I42 and I44 by reason of the attachment thereof to the respective surfaces of the said wheel 46 and such rotation will therefore be considered the rotation of a single cylindrical member designated 42.

At the extreme right as viewed in Fig. 3 there is provided the cylindrical member 43, only a por tion of which is shown in said Fig. 3. Same is constructed substantially the same as the cylindrical member 45 except that the major portion of said cylindrical member as is to the left of the wheel 47, while the major portion of the cylindrical member 49 is to the right of the wheel 44. The wheel 41 has a cylinder I43 secured to the rim 5| on the left face thereof, the construction of said cylinder its being substantially identical to that of the wheel I68 and including rectangular sections adapted to align with the window BI, one of which is shown at 54? in Fig. 2. The hub (not shown) of the wheel 4? has secured thereto a sleeve I36 in the same manner that sleeve 33 is secured to the wheel 24 and may be prevented from moving axially of the shaft by cotter pins and washers at opposite ends of the sleeve I 35. The left hand cotter pin and washer are shown at I63 and :48. The wheel N38 is mounted to rotate with the sleeve lite and wheel 47 and has a cylinder 559 secured to its rim I5i upon the left hand face thereof, the cylinder I59 having substantially the same construction as the cylinder I I2 albeit secured along an opposite edge. Sections (not shown) are provided upon the cylinder I53 adapted to align with the window 79. The construction of the wheel I38 is substantially identical with the construction of the wheel 88, albeit there is a slight difference in diameter to permit the cylinders of the respective wheels to telescope within one another without touching.

Rotation of the wheel 41 will cause simultaneous rotation of both transparent cylinders I45 and I59 by reason of the physical connection of the shaft I36 between wheels 41 and I33 and such rotation will therefore be considered the rotation of a single cylindrical member designated 43.

A fluorescent lamp 556 is intended to illuminate the windows I! to SI from the back thereof in order to provide as close to sunlight as possible. The left hand wall 24 is provided with a female socket I6I formed therein. A removable plug I62 is adapted to be carried by the socket I6I, said plug I62 having contacts I63 on its inner end adapted to be engaged by the male contact prongs I64 of the lamp I for supporting said lamp I60. A similar plug is provided on the right hand wall 25, although not shown, for supporting the opposite end of the lamp I66. Electrical power is obtained by means of a'conventional electrical power cord. I65 connected in the usual way. A ballast is shown at I66. Note that the lamp extends through all of the members 40, 4|, 42, and 43 and through the wheels of each member, whereby the members rotate about said lamp I60.

The socket I6I maybe formed on the left end of an elongated protector and reflector member I61 having a generally concave bottom portion and being open along the top thereof. Said reflector member extends through the members 60, 4|, 42, and 43 and is spaced from the lamp I60. Same serves as a stcpto limit rotation of the cylindrical members 40, M, 42, and 43 and prevents the arms such as for example, 53 or 52 from engaging against the lamp I60. In the spaces between the wheels 04 and 45, 45 and 46, and 46 and 41, the reflector member has tangential extensions of the sides thereof as shown at I10 and HI in Fig. 4. The similar members between the outer pairs of wheels are designated I12 and I19, and I14 and I15. Since all are alike, a description of one pair of such extensions will suffice. Thus the extensions'l'lil and HI have flanged edges I16 and I11 respectively, bent inwardly, and have a plurality of ears I18 and I19 on opposite extensions facing inwardly and cooperating with the flanges I16 and I11 respectively to form channels for the difiusing glass I80 disposed therein. The other diffusing glasses are designated I6I and I02, said glasses being positioned proper- 1y to illuminate all of the windows.

Prior to entering upon a description of the colored sections of the various transparent cylinders attention is directed to Fig. in which is shown a simple mechanism enabling the composite color seen through the composite window 19 to be seen as a small disc of color instead of a large rectangle. It is often found that comparison with a small area of color gives a different apparent result than comparison with a large area. It is therefore desirable to provide a mechanism for quickly enabling practically all of the large colored area to be masked with the exception of a small area in the center thereof so as to make comparisons therewith.

As shown in said Fig. 5, there is provided a masking member I90 which is curved to fit around the front of the housing below the wall 26 and adapted to extend behind the cover member 61, between it and the cylinder I42. A stop member I9I is secured to the wall 26, for example, by securing a lip I92 thereof between strap 1| and the backing member 69 as shown'in Fig. 4. There is a bottom lip I93 so that the free end of the masking member I90 is guided into the stop member IOI which is formed herein as a folded metal strip the folded end serving to stop movement of the masking member I90 upwardly and to the right as viewed in Fig. 5. The masking member I90 is somewhat wider than the window 19 at its top end, but tapers down to a narrow portion I94 bent upon itself at I95 to form an ear to which is pivotally secured a link I96 by means of the pivot I91. The link I96 is an elongate member pivotally supported intermediate its ends at I98 by the bracket I99 mounted upon the bottom wall 23 at 200. The end of the link I96 opposite the pivot I91 has a right angle bend forming an ear 20I pivoted to another link 202 The link 202 is pivotally mounted at the end opposite the pivot 203 to a member which is fixed relative to the housing 30. In the present instance it is the shaft 35 and for this purpose the end is formed with a loop 204 through which the shaft 35 passes. Intermediate its ends the link 202 is provided with a pivoted lever 205 pivotally secured at 206, and having a push button 201 secured to its upper end, said push button 201 protruding through the top wall 26 at the 'leftend of the housing 30 and having a stop member 208 secured to the buttonengaging the bottomof the wall 26 to prevent the button from being pushed through the wall 26. Obviously the wall 26 has a passageway for the button 201 which can loosely move therein. The right hand end of the lever I96 is urged downwardly by the coiled spring 209 secured to the wall .23at 2I0, and secured to the lever I96 at 2I I. This keeps the masking member I normally in the position shown in Fig. 5, with a rectangularopening 2I2 provided in the masking member in registry with the window 19. The outline of the Window 19 is shown in broken lines at 19 in said Fig. 5. When the button 201 is pushed downwardly, the lever 202 rotates downwardly about the shaft 35, the lever I90 rotates in a counterclockwise direction about the pivot I98 against the efiect of the spring 209, and the masking member I90 moves upwardly and to the right, until stopped by the stop member I9I. At this point, a small perforation 2I3 is in registration with the center of the window 19 so that only a small disc of color can be seen therethrough.

Each of the cylindrical members 40, AI, 42, and 43 has two cylinders as explained, both moving simultaneously as the respective wheels are turned. The cylinders are all formed of halftone colored sections printed upon the transparent material forming the cylinders. Half-tone plates are made by photographing subject matter through screens. In case the subject matter is a photograph, the various tones will cause var-,- ious exposures on different parts of the same plate, and the etching of the plate will cause different sizes of dots caused by the interstices of the screen. In the case of a uniform color area, of course, the dots will be uniform, and the size thereof will depend upon the time of exposure and etching. By careful control, plates can be made of uniform color, having the dots thereof also uniform, and in different values of dots. In this manner, the sections of the various cylinders are made up of rectangles of halftone color, having graduated values.

Referring to Fig. 8, the cylinder I00 has sections I02 to H0 which are half-tone color rectangles (in this case black, as will be explained) having respective values from 10% to 90%. The section I02 is preceded by a section IOI which comprises two halves 220, and 22I. As noted, the section 220 has the notation D. 0. below it, and the section 22I has the notation P-.,D." below it. Theoretically the section IOI should represent zero percent if the other sections are graduated by 10% each. In practice, however, there is no such thing as a zero percent half-tone plate. The smallest percentage dot is approximately 5% and this is referred to as pin dot and is shown in half 22I. It is often advisable to cut out the half-tone dots of a plate, and in this case there actually are no dots whatever, but merely a blank space in the actual plate. This situation is called drop out and is represented in half 220 by a complete absence. of color.

At the other end of the developed band shown in Fig. 8 as cylinder I00, the section. III which would normally be 100% of color isshown having two halves 222 and 223. 'Again, there is no such thing as a 100% half-tone dot in practise. Instead there is a plate having maximum size of dots and color which is known as pin hole and is approximately 'color. This is shown in half 223 which has the notation below the same P. H. meaning pin hole. The left half 22 is printed from a solid member, and not as a half-tone, and is thus designated Solid. Each of the sections I02 to I ID has the respective percentages of color indicated below the rectangular section. When any section appears at a window, the observer not only sees the color half-tone, but also the designatory indicia. Thus, in Fig. 2 it will be seen that section I05 appears at window TI, and the half-tone dots of the rectangular section are visible as well as the indicia below the same and reading 50% The cylinders I00, I29, I44, and I are all printed with sections identical with those shown in Fig. 8 on the left side of the figure, and designating the construction of cylinder I00. All halftone sections for these cylinders are printed in black, although the sections of the respective cylinders align and register with windows Tl, i8, 80 and 8| which represent and are marked respectively Yellow, Red, Blue, Black, as will be seen in Fig. 2.

In order to clarify the manner in which the half-tone sections are formed, there are shown in Fig. 9 three sections I55, I05, and it]? of the cylinder I00, corresponding respectively 'to 40%, and half-tone areas. A fifty percent area will be half color and half blank, and hence the dots form a perfect checkerboard. The section I05 has ten percent less color, and hence the'dots are slightly rounded, and the necks between the colored parts of the checkerboard are absent, thus rounding the dots and decreasing their size. In the case of the section I07, the solid portions of the checkerboard have run together causing the blank squares to become rounded, thereby providing the 60% half-tone area. The screen used in every case is identical, and the number of dots, their separation, and the rows are always identical. The differences lie in the size of the dots.

In printing half-tone colors, in the United 5 States there are certain practises which are followed in the trade which can be taken into account by my device. The various colors are printed with the half-tone dots aligned in different'manners producing thereby different screen patterns. By this it is meant that the coordinates of the screen used are changed in accordance with the color of the plate being made. Obviously' the plates used in printing the sections of cylinder I00 had the lines thereof perfectly aligned with vertical and horizontal and hence the axes of the Screen used in making the plates also aligned with vertical and horizontal. This represents a half-tone plate for the color yellow, and the symbolic alignment is shown in Fig. 16. The angle between the horizontal axis of the screen and true horizontal is obviously zero degrees. The screen in the case of the color red is rotated 15 clockwise, so that the angle 0 of Fig. 15 is 75. This is then the symbolic alignment of the color red. The color black is shown in Fig. 14 with the screen axes at 45 corresponding to the angle 1). The color blue is produced inhalf-tone plates with the screen rotated 15 in a counterclockwise direction to give the angle a as 105.

If desired, the sections of the cylinder I29 which represents the color red may be printed as 75 angle half-tones, the sections of cylinder I44 which represents the color blue may be printed as 105 angle half-tones, and the sections of the cylinder I45 which represents the color black may be printed as 45 angle half-tones. The purl may be printed on the backing member 59.

12 of the dots and the comparison thereof with the dots of a plate being processed. It is, therefore, immaterial as to the orientation of the rows of the dots, since the black areas of the sectionsare not used to obtain any composite colors.

Each of the cylinders H2, I32, I50, and I42, however has sections printed as rectangular half-tone colored areas. Taking first the cylinder H2, same is shown developed in Fig. 8. The sections are wider than those of cylinder I00 in order to enable the entire section to appear at the window 15!. Again, the section's II4 to I22 inclusive are printed as half-tones having the values 10% to inclusive, but in this case the half-tones are actually printedin the color yellow. The axis of orientation is 0 as ex-' plained. The section H3 has two halves, 234, and 235. The left half 234 is a yellow drop-out and hence perfectly blank, while the right half is a pin dot section and hence has 5% of yellow half-tone color. There are no indicia on the cylinder H2 similarto the numerals of cylinder N30. The designations drop out and pin dot are placed at 236 and 231 above window 19 and The section I23 has two halves 238 and Y235 which are respectively solid yellow, and pin hole half-tone yellow. Indicia 2 40 and MI below window 19 have the designations solid and pin hole" to point this out.

In like manner, the cylinder I32 which is the mate of the cylinder I29 has graduated sections or" red half-tone areas oriented the conventional 75 with end sections formed in red exaeu as sections H3 and I23; the 'cylinder I42 which is the mate of the cylinder I44 has graduated sections of blue half-tone areas oriented the conventional with endsections formed in blue exactly as sections I I3 and I23; the cylinder I50 which is the mate of the cylinder I45 has graduated sections of black half-tone areas oriented the conventional 45 with end sections formed in black exactly as sections 9 l3 and I23.

The cylinders and numerals It of each cylindrical member i, 52 and 43 are all matched as to percentages so that-at the same position that a black half-tone section and its. indicia appears at a small window, a large colored halftone area of the identical percentage appears at the large window is, while the wheel which moves the cylindrical member willhave the edge bearing the indicia' number corresponding to the percentage appearing above the 'wall 25. Thus, as shown in Fig. 2, with the wheel I2 set at the point where indicia I5 reads 5 corresponding to 50%, there appears at window H the 50% half-tone black section m5 with its indicia reading 50%, while at the window '58, the 50% yellow half-tone section IIS appears in registry with the predetermined colored sections of the other cylindrical members. Likewise'the wheel :35 is set at 1 which means that there is a black half-tone area of 10% value at the window I8 including the indicia 10% and al()% red halftone area in registry with the window '19 and the yellow half-tone area; the wheel 45 is set at 9" which places a black half-tone area of 90% value at the blue window 3d including the indicia 90% while there is a 90 blue half-tone section in registry with window I9 and the yellow and red sections; the wheel 4'! is set at 2 which places a 20% black half-tone section at window 8I including indicia 20% and a 20% black halftone section in registry with window '19 and the already present yellow,-red, and blue sections.

13 With the above described setting, if the lamp I60 is turned on (switch buttons are shown protruding from the top section 2'! at 24c and 24!) the observer will see through the window 19 a composite color made up of half-tone sections having values as follows:

50% yellow red 90% blue black and the composite color will have substantially the identical appearance as though it were printed from four plates having the half-tone values designated above.

With such setting, the observer can examine the size of the dots of the half-tone section representing each color at the respective windows 11, 18, 8B, and 8|. Since these sections are all in black, the comparison with the actual plate is a simple matter, enabling the observer to treat the plate for changing the size of the dots, etc. The notation Key under the black window is merely an indication that the black carries the principal parts of the color composition.

A symbolic representation of the mating cylinders of each cylindrical member is shown in Fig. 10 in order to demonstrate that the sections having the same percentages move simultaneously to identical positions.

The use of the solid, pin dot, pin hole, and drop-out sections is believed obvious. In any event, where a maximum or minimum percentage process color is used to form a composite color the observer has the effects produced by using half-tone maximum or solid at the same time, or the effects of using half-tone minimum or drop-out at the same time. 7

In Figs. 11 and 12 there is shown the manner that the various sections combine to produce a composite color. The sections from the colored cylinders H2, I32, I42, and I50 combine under the window 19, and the colored dots are aligned as shown in perspective in Fig. 11, as shown in greatly enlarged plan in Fig. 12, and as shown in general effect inFig. 17 which is a plan view on an enlarged scale, although not as greatly enlarged as Fig. 12, of the composite color appearing at the window 19. the distances between rows of dots is identical although the size of the dots may be different between sections, representing different percentages.

It will be noted that the order of colors reading from left to right on the device is yellow, red, blue and black. This is the order in which the colors are printed commercially. A given color can, therefore, be designated by a four digit number representing the numerals on the respective wheels. Thus, the color shown in the composite window 19 of Fig. 2 could be designated 5192, meaning that the composite color is composed of the percentages 50, 10, 90 and 20. In

the construction of this device it was deemed more important to have the order of colors from left to right correspond to the usage than to have the central colored cylinders nest within one another in the printed order. As it happens, the only colors interchanged from conventional are the blue and black, but obviously a construction could be made in which the actual colors making up the composite color are arranged in the order of printing.

It is also desired to point out that the printed sections of all cylinders need not be made up of Note from Fig. 12 that 14 half-tone areas but could just as easily be made of tints applied in any desired manner, and further there need not be four cylindrical members, but there could just as easily be 3 or 2 or 5, etc.

With respect to the use of my device, obviously many uses suggest themselves at once. Artists would find use for the device to see the actual swatch of color reproducible from four process inks. Designers, especially those in the package field are able to show their clients a variety of color swatches and carry a complete campaign through, using the colors actually chosen by sight. Color photographers could use the device in order to determine how much or how little any of the colors vary from a desired effect, and in this case, the black cylindrical member is set at zero and the drop-out section is used. Engravers, lithographers and printers can use this device for checking and correcting color proofs, checking screen negatives and positives, checking production, and in many other Ways. Furthermore, executives can follow carefully and accurately printing, engraving and photographic processes by means of this instrument.

It is believed that this invention, its mode of construction and assembly, and many of its advantages should be readily understood from the foregoing without further description, and it should also be manifest that while a preferred em bodiment of the invention has been shown and described for illustrative purposes, the structural details are nevertheless capable of wide variation within the purview of this invention as defined in the appended claims.

. What'is claimed and desired to be secured-by Letters Patent of the United States is:

l. A device of the character described compris ing a housing having one window designated as a composite color window and a plurality of other windows, a shaft in said housing, a plurality of wheels independently mounted for rotation on said shaft within the housing, said wheels being co-axially mounted on the shaft, means for rotating each wheel from outside the housing, each wheel having a pair of translucent cylindrical members rotatable'therewith, one of each pair of cylindrical members having a peripheral band of a predetermined process color used in color print ing and each said band having a plurality of colored areas of sequentially graded intensity, the second of each pair of cylindrical members having intensity and color identifying elements arranged parallel to the colored areas so as to rotate simultaneously therewith, said wheels being spaced along the shaft with the said first cylindrical member of each wheel in overlapping relationship one relative to the other and in registration with said composite window for viewing a composite color resulting from a single colored area of each first cylindrical member registering with said composite window and with the second cylindrical member of each wheel having its identifying elements adapted to register with one of said other windows, said wheels being rotatable so as to dispose a composite color opposite said composite window and the individual elements which make up the composite color, both as to intensity and kind, opposite said other windows.

2. A device of the character described comprising a housing having one window designated as a composite color window and a plurality of other Windows, a shaft in said housing, a plurality of wheels independently mounted for rotation on said shaft within the housing, said wheels being QQBQLQSS 15 co-axially mounted on the shaft, means for rotating each wheel from outside the housing, each wheel having a pair of translucent cylindrical members rotatable therewith, one of each pair of cylindrical members having a peripheral band of a predetermined process color used in color printing and each said band having a plurality of colored areas of sequentially graded intensity, the second of each pair of cylindrical members having intensity and color identifying elements arranged parallel to the colored areas so as to rotate simultaneously therewith, said wheels being spaced along the shaft with the said first cylindrical member of each wheel in overlappi relationship one relative to the other and in reg. tration with said composite window for viewing a composite color resulting from a single colo ed area of each first cylindrical member re v with said composite window and with the second cylindrical member of each wheel having identifying elements adapted to register with one of said other windows, said wheel's being rotatable so as to dispose a composite color opposite said composite "ind'ow and the individual e1ements which make up the composite color, ooth as to intensity and kind, opposite said other windows, said intensity and color identifying elements comprising printed half-tone swatches having predetermined dot sizes representing the percentage of color in the respective color area corresponding thereto, said color areas ccinpr' ing printed color half-tone each wh having the areas of its said one cylindrical lllciirher of a clifierent process color. I

3. A device of the character described con rising a housing having plurality of windows of which one is designated a composite color window, a shaft in said housing and color analyzing means within the housing adapted to be illuminated and viewed through said windows, said means comprising a plurality of wheels, co-axially mounted and independently rotatable on said shaft, each wheel having two cylindrical trans" lucent members with graded'piginented elements thereon similarly positioned circumferentially and movable simultaneously with said wheel, one

of said two cylindrical members having its elements in standardized color withsaid elements difiering in color, the other of said two cy1indrical members having elements of a density identifying character, the cylindrical members having standardized color elements being of slightly different circumference, said wheels being spaced along the shaft with the cylindrical members having standardized color element's arranged in overlapping relationship one relative to the other and aligned with said composite color window to 1 6 produce a composite color thereat and each oi the said other cylindrical members aligned with one of the said other windows and spaced from its corresponding standardized color cylindrical member, and an elongate light source in the housing between the axis and the cylindrical members and extending through said wheels whereby to position said light source immediately behind the windows.

4. A device of the character described comprising a housing having one window designated as a composite window and a plurality of other windows, shaft means in said housing, a plurality of wheels independently mounted for rotation on said shaft means within the housing, said wheels being co-a'xially mounted on said shaft means, means for rotating each wheel from outside the housing, each wheel having a pair of translucent cylindrical members rotatable therewith, one each pair of cylindrical members having a peripheral band of a predetermined process color used incolor printing and each said band having a plurality of color areas of sequentially graded intensity, the second of each pair of cylindrical members having intensity and color identifying element-s arranged parallel to the colored areas so as to rotate simultaneously therewith, said wheelsbeing spaced along the shaft means with the first cylindrical member of each wheel in overlapping relationship one relative to the other and in registration with said composite window for viewing composite color resulting from a single colored area of each tfir'st cylindrical member registering with said composite window and with the second cylindrical member of each wheel having its identifying elements adapted to register with one of said other windows, said wheels oeing rotatable so as to dispose a composite color opposite said composite window and the individual elements which make up the composite I color, both as to intensityand color, opposite said other windows.

HERBERT 'W. References Cited in the file of this patent v UNITED STATES PATENTS Number Name Date 329,078 Phillips Oct. 27,1885 1,049,997 Coe Jan. '7, 1913 1,308,512 Taylor July 1, 1919 1,414,857 Brandvein May 2, 1922 2,120,499 Mackay -1 June 14, 1938 2,196,271 Olson Apr. 9, 1940 2,476,580 Bergman July 19, 1949 2,522,723 Rookyard Sept. 19, 1950 

